ABSTRACT We report the case of a woman who is 56 years old that presented abdominal pain and fever. She also referred jaundice, dark urine, pale stools and a weight loss of 10 kg since the beginning of the case. She did not refer melena, nauseas or vomits. The abdominal ultrasound revealed a normal liver, dilatation of the intrahepatic bile ducts, choledocus of 37 mm in the middle third and 14 mm at retropancreatic level with a suspicion of calculus and a distended gall bladder vesicular with biliary mud. An obstructive jaundice was diagnosed and an endoscopic retrograde cholangiopancreatography was indicated showing a tumor aspect of the larger papilla with 2 to 2.5 cm of size, with ulceration close to the bud orifice and irregular surface. The endoscopic resection of the tumor was proposed. The biopsy reported a villous adenoma with changes of severe dysplasia and an in situ carcinoma with compromises of the endoscopic resection limits. The abdominal CAT did not show any metastasis images. A cephalic duodenopancreatectomy was indicated. The pathologic anatomy reported an in situ adenocarcinoma of the ampulla of Vater with surgical limits and no evidence of neoplasia. The pancreatic lymphatic nodes did not show any metastatasis evidence either. There was a good evolution after the surgery and the patient was discharged 15 days post-surgery. After two years of follow-up the patient is clinically asymptomatic and there is no diagnostic evidence of residual tumor.